U.S. Navy looking at obtaining fuel from seawater

Tell someone that you’ve invented a car that runs on water and they're liable to report you for fraud. That hasn’t stopped scientists and engineers at the U.S. Naval Research Laboratory (NRL) who want to run warships on seawater – or at least, to turn seawater into jet fuel. This may sound like they’ve been standing too close to the ether again, but the idea is to extract carbon dioxide and hydrogen from seawater and then convert these into jet fuel by a gas-to-liquids process. If this proves practical, American naval vessels could refuel themselves at sea.

At first, it seems odd that the NRL wants to make jet fuel, but many modern warships now run on gas turbines, a type of jet engine. Every year the U.S. Navy’s fleet of 15 oilers carries 600 million gallons (2.27 billion liters) of fuel to ships at sea. This is a major logistical problem made worse by dependence on hostile or unstable nations who may cut off or interfere with fuel supplies in times of crisis. Needless to say, a ship that can make its own fuel while underway would be an advantage.

A U.S. Navy ship being refueled at sea

Seawater contains about three percent carbon dioxide in the form of dissolved carbonic acid, carbonate and bicarbonate. That’s 140 percent more than air. Along with the hydrogen bound in the water molecules, there’s all that’s needed to make hydrocarbon fuels at sea. The tricky bit is how to do it.

According to research chemist Dr. Heather Willauer, the NRL’s approach is based on established technology. "The reduction and hydrogenation of CO2 to form hydrocarbons is accomplished using a catalyst that is similar to those used for Fischer-Tropsch reduction and hydrogenation of carbon monoxide,” she said. “By modifying the surface composition of iron catalysts in fixed-bed reactors, NRL has successfully improved CO2 conversion efficiencies up to 60 percent."

The Fischer-Tropsch reduction was invented by Franz Fischer and Hans Tropsch in Germany in the 1920s. It converts coal, natural gas or biomass into fuel by means of iron or some other catalyst and is used commercially in countries with abundant coal, but little oil. Despite being very inefficient and costly, the U.S. Defense Department has long been interested in it.

The NRL process begins by extracting carbon dioxide and hydrogen from seawater. To do this, it uses a three-chambered electrochemical acidification cell. As seawater passes through this, it’s subjected to a small electric current. This causes the seawater to exchange hydrogen ions produced at the anode with sodium ions. As a result, the seawater is acidified.

An Electrochemical Acidification Carbon Capture Skid, used for the process

Meanwhile, at the cathode, the water is reduced to hydrogen gas and sodium hydroxide is formed. The cells recover dissolved and bound carbon dioxide by re-equilibrating carbonate and bicarbonate to carbon dioxide gas from the acidified seawater. The end product is hydrogen and carbon dioxide gas. As a bonus, the sodium hydroxide is added to the leftover seawater to neutralize its acidity.

In the next step, the hydrogen and carbon dioxide are passed into a heated reaction chamber with an iron catalyst. The gases combine and form long-chained unsaturated hydrocarbons with methane as a by-product. The unsaturated hydrocarbons are then oligomerized – that is, they are made to form longer hydrocarbon molecules containing six to nine carbon atoms. Using a nickel-supported catalyst, these are then converted into jet fuel.

The process has been tested under open ocean conditions in the Gulf of Mexico, and the NRL is now working to improve the process and scale it up to practical levels. The estimated cost of the fuel is projected to be between US$3.00 and $6.00 per gallon (US$0.79 - $1.58 per liter) and that may be something of a problem because the current price of jet fuel is about $3.30 per gallon ($0.87 per liter), which makes the NRL product potentially almost twice as expensive.

Another problem is that processes based on the Fischer-Tropsch reduction are very energy intensive and inefficient, which adds to the cost. Also, the end product is very pure and this can cause lubrication and sealing problems in engines.

However, the big question is, where does the energy come from to make the fuel while at sea? Most Fischer-Tropsch reduction processes work because the raw material is itself a fuel. To make fuel from coal, you burn coal to run the process. The same goes for natural gas, biomass and other examples. With the NRL process, the raw material is seawater, so what is running the machinery? The jet fuel produced is only an energy storage medium, not an energy source. To use that is like trying to lift yourself off the ground by yanking on your belt. Until that question is answered, a vital piece of the puzzle is still missing.

David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

A nuclear carrier might use a system like this to generate fuel for its planes or accompanying vessels.

Apart from that, perhaps a diesel-powered ship might generate JP5 for the helicopters and drones it operates?

Jon A. 26th September, 2012 @ 02:52 pm PDT

It would be far more practical to just use nuclear power for the ships although as a method for producing fuel for aircraft it has merit.

Slowburn 26th September, 2012 @ 02:59 pm PDT

Is waste heat from a gas turbine hot enough for this process?

kwarks 26th September, 2012 @ 04:03 pm PDT

At $1.58 / litre I do this to make fuel for my car which costs about that much. I could just drop a couple of hoses into the canal outside my house and fuel up. Assuming I had a batmobile, which lets face it, we all want.

Scion 26th September, 2012 @ 06:58 pm PDT

Have a conventionally fuelled resupply ship fitted with a very large scale version of this equipment. Each ship could potentially serve multiple squadrons, and with no combat duties they can concentrate on fuel production for the majority of time at sea.

A nuclear powered craft could probably handle the power requirements, especially considering these ships don't need to be particularly fast.

Richard Belihomji 26th September, 2012 @ 07:33 pm PDT

So... if the Navy now see merit in this, when will we start using it for cars?

Murray Smart 26th September, 2012 @ 07:58 pm PDT

I am glad they added that last paragraph because this is very much the dumbest idea and article I have ever read.

Why don't we just research running our ships on "happy thoughts" because that is more likely then a ship"refueling itself using sea water as fuel".

Seriously I do understand all the process they described, the whole concept is beyond absurd.

Michael Mantion 26th September, 2012 @ 09:40 pm PDT

Where does the energy come from? How about off shore wind turbines.

Windsor Wilder 26th September, 2012 @ 11:53 pm PDT

The obvious and only way this makes sense is that nuclear carriers would produce fuel for their planes this way.

Joe Acerbic 27th September, 2012 @ 02:23 am PDT

Other people at the same lab have been doing Cold Fusion work since 1990 so that's where the energy will come from. It will be D2/ Pd or H2 Ni gas phase low energy nuclear reactions producing both heat and electricity to power the reaction. These cold fusion reactions run slow and steady and don't like variable loads. Powering a steady chemical conversion system that then powers the variable loads: turbines; small boats and drones makes perfect sense.

Wesley Bruce 27th September, 2012 @ 02:58 am PDT

Some background: the navy was experimenting with algae based jet fuel until the Republican congress prohibited them from buying any petroleum alternative that cost more than the fuel it was replacing unless it was made through a Fisher-Tropsch type catalytic process. The Republicans goal was to support the oil and coal sectors while preventing the Obama administration from getting serious about anthropogenic climate change. It looks like the navy has found a green workaround. Iceland, Norway, Ireland etc will probably be interested in the results.

Windsor Wilder 27th September, 2012 @ 05:43 am PDT

Okay, here's the plan: take a supertanker, fit its multiple-football-field-sized deck with windmills and solar panels, install this conversion plant in it, run it off of this generated power, and pump the newly fabricated fuel into the waiting tanks! Yay! Green & Clean & ready for ! World's problems solved! :-)

MzunguMkubwa 27th September, 2012 @ 05:59 am PDT

Who is the dumber? the "geniuses" who are developing the system or the politicians who funded such idiocy?

ugosugo 27th September, 2012 @ 06:14 am PDT

I agree that nuclear powered ships are the only way to go to do this kind of thing. The line in the article is misleading... "American naval vessels could refuel themselves at sea" does not necessarily mean creating fuel to power the ship making the fuel.

A nuclear powered tender could produce the fuel and maintain old fashioned hydrocarbon burners, but a hydro burner will never "make it's own fuel". A carrier that could fuel it's own aircraft without the oilers would drastically reduce logistics and costs so would be a worthwhile project. As they mentioned in the article it's a huge expense and liability to have to rely on tanker ships.

VirtualGathis 27th September, 2012 @ 06:17 am PDT

I don't know what all the negative comments are about. Like many comments said, a nuclear powered aircraft carrier can be fitted with the system. The tactical advantage will be enormous, since the US has probably the most powerful air force in the world.

bio-power jeff 27th September, 2012 @ 07:47 am PDT

What is wrong with people, I mean people know stats on stupid stuff like sports or who won american idol, but have no clue about important things such as water to fuel. One guy commented about Obama and republicans, really?

There is more energy in a 4 ounce cup of water, than there is in 5 GALLONS of gasolene. There have been MANY people who have developed ways to run power generators, home heat, and cars off water. Myst#riously things seem to happen to most of these people right before the world can see what they have done. Look it up on google, and youtube, or bing, or whatever search engine you use. Type "water to fuel".

Even back in the 1960's a man evented a carburator that would make a car go hundreds of miles off one gallon of gas. This man was forced to cease operations, sell his plans, and threatened with life in prison, if further pursued. There are even power generators that produce enough power to run homes and itself, without any fuels. So why would any president, or anybody, want to invest so much into special fuels, insteaf of simple hydrogen? Because they cant control rain, and the earth is 75% water, and you can sell that or tax it.

We are not our government any longer, and this means we are no longer free. There are laws, rules, regulations, that are designed to not allow true freedom. One man stands, and he disapears...........

peteepositive 27th September, 2012 @ 10:19 am PDT

Oh dear - I hope they aren't going to spend taxpayers money on this absurd idea! Sounds to me that they will be burning hydrocarbons to supply the energy to make more hydrocarbons at a very low yield. Duh! Who's in charge of this project - a schoolboy?

I think the navy is going off-track. They would better be looking at Rossi's LENR type technology.

Adrian Akau 27th September, 2012 @ 05:38 pm PDT

re; Adrian Akau

When Rossi gets rich selling electricity we can start to take his claims seriously.

Pikeman 27th September, 2012 @ 10:39 pm PDT

For the uniformed the process of converting Co2 into a fuel source is already done. Look up Blue fuel.com.You can find a short video on YouTube also.

Darryl Goodman 28th September, 2012 @ 11:03 am PDT

Anytime these topics come up the "perpetual energy" quacks seems to come out of the wood work. Obviously they didn't invent perpetual energy, the reason for the technology is not because this technology is any more efficient but because the military is a machine and that machine runs on petroleum which could at times be a problem given the levels of crazy displayed by some of the OPEC nations at times.

Using a nuclear powered ship that creates hydrogen fuel from water is almost certainly more expensive than today's standard fuel prices but an expensive plan B is still better than not having a plan B.

I am sick of seeing educated people making this claim that cars could easily get 75 - 100 MPG and it is all just some big oil cover up. Sure there are some super efficient cars in Europe but they are ~1.4 liter diesel engines in 1,000 lb cars. Nobody is getting 55 MPG with anything close to the size and power of an F-150 out of an ICE.

Daishi 30th September, 2012 @ 09:47 pm PDT

Nuclear powered source to make fuel for naval aviation and other 'defendant' craft is a good route to go. HOWEVER, the germ of a better idea is found in the comments as well! Stationary offshore manufacturing platforms can collect virtually free wind, solar, and tidal power to MAKE high value portable fuels! No need to drill for oil, just pull the carbon out of the ocean at these sites. This is a truly green method of recycling carbon through the biosphere! (And reduce what we're pumping out of the ground)

Dr Dick 1st October, 2012 @ 11:03 am PDT

Why bother with the carbon? Burning hydro-carbons is simply releasing the carbon into the environment. Why not just plug your Nuclear generator into the sea and harvest the Hydrogen? Bun that in your turbine, and get - water. That's really simple, and really cheap.

Matthew Bailey 1st October, 2012 @ 11:27 am PDT

FIFE was deliberately sunk (during a "SINKEX") on 24 Aug 04.

Craig Walker 11th October, 2012 @ 01:48 pm PDT

Diachi above tries to say the only cars getting 70-80 MPG are 1,000 pound cars with tiny engines. Sorry to give you actual facts but the VW Golf Blue Motion diesel has over 100HP, weighs 2,800 pounds+ Passengers, fuel etc....and can still do 70-80 MPG with a 60MPG Average even around town, highway style running. Come on guys STOP making out every good idea is bad.....its oil companies that won't allow true fuel from water as per hydrogen generation etc, as major economies are built around oil so they won't allow true geniuses to bring anything to market that would generate fuel from easily available water.